The uses of cardiovascular risk estimation
Strokes, heart attacks and peripheral arterial disease - cardiovascular risk is about common and important ill health outcomes. Any moves you make to reduce this risk, will have lots of more immediate benefits, however. Nearly everyone feels better when they exercise and lose weight. If you are seeking advice on your personal cvs risk, it is worth understanding about relative and absolute risk reduction. If you have a very small risk of something happening, even a 50% (relative) reduction in that risk is not very important. The absolute risk reduction will also be very small. The National Heart Foundation of New Zealand has published an absolute risk calculator which is quick and easy to use...
This is just a portion of the two page chart, which takes 6 factors into account (those shown plus gender.) One often ends up with a result between two colors, which is still quite easy to use...
The chart uses total chloesterol / HDL ratio, as this is a much better predictor of coronary artery disease risk than is the total cholesterol alone. Always make sure that a HDL is done whenever your cholesterol is measured.
I use the right hand figures, of the number of people in the same situation now, who would need 5 years of conventional treatment to prevent one episode of cvs illness.
As an illustration, for a 50 year old male, BP 180/105, TC/HDL ratio 8, non diabetic and non smoker, the absolute risk is 15-20%.
The NNT is 16. Total expected events untreated are 3, so the figures are as seen. Two events not prevented, one prevented and 13 people in the clear for now.
Presented with these figures, one person might say if they had one chance in 16 of winning a lottery, they would buy tickets for five years. Another person might say that taking drugs for 5 years, with the risks and doctor visits entailed, all for one chance of benefit in 16, would not interest them. I do point out as I present the figures, that the two episodes of illness may not have been as severe, and that the other 13 people may have not developed arterial disease as much, reducing future risk. The benefits of various medications are commonly quoted as percentage relative risk reductions. These don't mean much without the above type of information.
Homocysteine should be included in cardiovascular risk tests
This substance is a partial breakdown product of methionine, one of the building blocks of our proteins.The breakdown cannot be completed nor reversed, because of lack of one of four substances needed for these jobs. The four factors are vitamins B6, 9 and 12 and betaine. Homocysteine has the same history in medicine as cholesterol. Families were found who had very high levels due to genetic mutations, and very increased cardiovascular risk. Increased homocysteine levels are associated with 10% of the variance in risk between middle aged males. Cholesterol accounts for a smaller proportion Correcting the appropriate deficiency often relieves symptoms such as fatigue, balance problems and sleep disturbance. It is definitely not a case of pie in the sky...
Full versions of cardiovascular risk calculators
This first one uses imperial units, as in USA
Coronary Heart Disease Framingham Point Scores
This one uses SI units as in Australia
Full copy of New Zealand risk calculator
Waist-hip ratio and intra-abdominal obesity
The MacArthur Successful Aging Study, a longitudinal study of high-functioning men and women, average age 74, was recently reported (in the October '09 issue of the Annals of Epidemiology.)Waist-hip ratio was found to predict all-cause mortality in these older adults. Whether over eating and under exercising are purely habits or due to our belief systems or emotional stuff, this whole scenario often offers the greatest possibilities for useful change in our lives. You can feel better as well as living longer, which is really more to the point. If you're in the mood for radical change, look at Leslie Kenton's book
"The New Raw Energy."
Glycosylated haemoglobin ( HbA1c ) is an independant risk factor
Sugar sticks to protein, at a rate dependent on the sugar level in the blood. This is measured in our haemoglobin, to monitor blood sugar levels in diabetes. It is one of the factors which accelerate aging, and has just been shown6 to predict cardiovascular disease and all cause mortality in people without diabetes.The best HbA1c was 5-5.4, with progressively more trouble as levels rose, but also higher mortality if <5%. This is an example of the "J-shaped curve" often seen, where too much or too little of something indicates trouble.
Latest on diagnosis of diabetes from American Diabetes Association
Revised recommendations for diabetes diagnosis - hemoglobin A1c (HbA1c) is an easier diagnostic test, not requiring the 12 hours water only and two hours waiting needed for the OGGT used now.The new recommendations are published December 29 in the January supplement of Diabetes Care. They believe that use of the HbA1c will encourage more people to get tested for type 2 diabetes and help further reduce the number of people who are unaware of this cardiovascular risk factor. Type 2 diabetes actually can be prevented, as long as lifestyle changes are made while blood glucose levels are still in the pre-diabetes range."
Peridontal gum disease and cardiovascular risk
A really hot topic in cardiology research is the "vulnerable plaque." Thin-cap fibroatheroma is thought to be more at risk of rupture and subsequent blood clot blocking the artery.Intravascular ultrasound is being used to find ruptured plaques in people with unstable angina. Why do plaques rupture or get surface erosion? This is one possible connection with peridontal disease, which is a known potent risk factor for heart attacks. Gum disease can increase a general tendency to inflammation throughout our body, and can lead to dissemination of germs via our blood stream. These can then damage plaques.
Treating gum disease to protect your heart
The spasm of resistance vessel (S-RV) concept
The spasm of resistance vessels may directly induce symptoms in ischemic diseases.This is a credible theory1, and opens possibilities for treatment aimed at reducing the risk of spasm, such as magnesium supplements.
Vagal withdrawal & Sympathetic activation, causing arrhythmias
Reduced baroreflex sensitivity after heart attacks, and low heart rate variability, both indicating vagal underactivity, have been shown to be associated with substantially increased risk of subsequent sudden death.After recovery from ventricular fibrillation, people have markedly increased cardiac sympathetic activity. This dysfunction of the autonomic nerve control of the heart increases with age. It can be a target for nutritional and herbal support programs and a reason to meditate. Omega-3 oil supplements reduced heart rate and increased heart rate variability in depressed patients with coronary heart disease, in one study7.
Microembolism of vasa vasorum of coronary arteries
The tiny blood vessels which supply nutrition to the walls of the coronary arteries themselves, have been shown to get blocked. This may be important in the development of plaque instability, or even the development of plaque in the first place. See3 http://www.thincs.org and http://www.ravnskov.nu/cholesterol.htm
A2 milk - the way it used to be ( may have been better)
A strong relationship has been found2 between the amount of A1 β-casein consumed and heart disease mortality.Apparently cows used to produce A2 beta casein, and still do in some areas of the world. The difference is only one amino acid, but it changes the way our body uses the milk. This genetic variant may have come from intensive dairy cattle breeding. A2 milk - another way to reduce your cardiovascular risk.
Can infection cause heart disease?
Chlamydia pneumoniae has been found in the fatty plaques from coronary arteries, and may help cause surface damage and instability.A very good discussion of this, from 2000, is at http://qjmed.oxfordjournals.org/cgi/content/full/93/6/375
References and further notes for cardiovascular risk assessment
1. Med Hypotheses. 1999 Sept 53(3):200-209.2. Ischaemic heart disease, Type 1 diabetes, and cow milk A1 beta casein. Laugesen M & Elliott R, New Zealand Medical Journal. 2003 Jan 24;116(1168):U295 See abstract at http://www.ncbi.nlm.nih.gov/pubmed/12601419 3. "Vulnerable Plaque Formation from Obstruction of Vasa Vasorum by Homocysteinylated and Oxidized Lipoprotein Aggregates Complexed with Microbial Remnants and LDL Autoantibodies" Uffe Ravnskov and Kilmer S. McCully Annals of Clinical & Laboratory Science, vol. 39, no. 1, 2009
Several studies have suggested that the FRS overestimates the cardiovascular risk in Japanese-American and Hispanic men, in Native American women, and in European and Asian populations.
The SCORE (Systematic Coronary Risk Evaluation) project4 better predicts cardiovascular risk for European patients. There are now multiple country-specific versions of the SCORE system. It uses age, sex, total cholesterol, total cholesterol to HDL-C ratio, systolic blood pressure, and cigarette smoking. It has separate risk scores for higher risk and lower risk regions of Europe.
A nonlaboratory-based model5 using the same risk factors from the FRS but excluding HDL, and total cholesterol and adding body mass index, gave almost identical ability to accurately discriminate CVD. In my opinion this just shows the weakness of the relationship between cholesterol and heart disease.
4. Conroy RM, Pyorala K, Fitzgerald AP, et al. Estimation of ten-year risk of fatal cardiovascular disease in Europe: the SCORE project Eur Heart J 2003;24:987–1003. 5. Gaziano TA et al. Laboratory-based versus non-laboratory-based method for assessment of cardiovascular disease risk: the NHANES I follow-up study cohort Lancet 2008;371:923–31.
6. Selvin E et al. Glycated hemoglobin, diabetes, and cardiovascular risk in nondiabetic adults. N Engl J Med 2010; 362:800-811. (Analysis from the Atherosclerosis Risk in Communities (ARIC) study, after median follow up of about 14 years.) 7. Carney RM et al Effect of Omega-3 Fatty Acids on Heart Rate Variability in Depressed Patients With Coronary Heart Disease. Psychosom Med. 2010 Aug 17.
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